When installing a major OS update it's often worthwhile to do a clean install. As a shameless plug of some free software I made, Install Disk Creator will make you a bootable USB installer out of any USB disk you have laying around made from the macOS installer that you download from Apple.
"Install Disk Creator will make you a bootable USB installer out of any USB disk you have laying around made from the macOS installer that you download from Apple."
Wow - thank you! I have a half-page of self-written documentation about turning an apple installer into a bootable USB that I hope to never have to use again ...
While I think Disk Creator is awesome for certain I’ve never found that a fresh install is needed for macOS upgrades. They have maybe the best upgrade process in the biz right now.
Honestly, I haven’t even bothered doing that with Windows in a pretty long time—maybe since the 7 to 8 transition, after which they’ve had a pretty robust upgrade path. About the only place I do do that regular is on Linux, but that’s because it’s stupidly easy to do so due to the packet managers, not because I actually have to.
While I’ve not felt any particular pain from updating, other than perhaps some binaries from homebrew that needed to be recompiled, i've got an enormous ~/Library folder along with a few hundred GBs of other cruft accumulated through several upgrades of OS X over the last four or five years. Most of it is applications not related to the OS, so not blaming Apple here, but the opportunity to rebuild from a clean slate is welcome for sure.
It's only an opportunity to re-evaluate what autoruns at startup and what you want running in the background. This means people feel faster once they delete all of those things. You'd do just as well by removing them yourself.
If you have more than one Mac you might want to create a USB install stick so that you only need to download the installer once, on a Mac that you'll upgrade later.
